Application.CancelQuit  

// Delays quitting for 2 seconds and
// loads the finalsplash level during that time.

var showSplashTimeout : float = 2.0;
private var allowQuitting : boolean = false;

function Awake () {
// This game object needs to survive multiple levels
DontDestroyOnLoad (this);
}

function OnApplicationQuit () {
// If we haven't already load up the final splash screen level
if (Application.loadedLevelName.ToLower() != "finalsplash")
StartCoroutine("DelayedQuit");

// Don't allow the user to exit until we got permission in
if (!allowQuitting)
Application.CancelQuit();
}

function DelayedQuit () {
Application.LoadLevel("finalsplash");

// Wait for showSplashTimeout
yield WaitForSeconds(showSplashTimeout);

// then quit for real
allowQuitting = true;
Application.Quit();
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
public float showSplashTimeout = 2.0F;
private bool allowQuitting = false;
void Awake() {
DontDestroyOnLoad();
}
void OnApplicationQuit() {
if (Application.loadedLevelName.ToLower() != "finalsplash")
StartCoroutine("DelayedQuit");

if (!allowQuitting)
Application.CancelQuit();

}
IEnumerator DelayedQuit() {
Application.LoadLevel("finalsplash");
yield return new WaitForSeconds(showSplashTimeout);
allowQuitting = true;
Application.Quit();
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

public showSplashTimeout as single = 2.0F

private allowQuitting as bool = false

def Awake():
DontDestroyOnLoad(self)

def OnApplicationQuit():
if Application.loadedLevelName.ToLower() != 'finalsplash':
StartCoroutine('DelayedQuit')
if not allowQuitting:
Application.CancelQuit()

def DelayedQuit() as IEnumerator:
Application.LoadLevel('finalsplash')
yield WaitForSeconds(showSplashTimeout)
allowQuitting = true
Application.Quit()